1. Field of the Invention
The present invention relates to a high-performance; small die size, and low-power dissipation decimation filter.
2. Discussion of the Related Art
Conventional analog filter solutions require switching between different filters or different filter components when processing information coded according to different standards or different channel bandwidths. For analog filters to achieve the required narrow transition bandwidths and high stopband attenuations, precise component tolerances are required. Precise component tolerances are difficult to achieve on-chip, necessitating the use of off-chip components, thereby resulting in increased system cost. Additionally, temperature compensation and aging are also often required.
Conventional digital filter approaches use finite impulse response (FIR) filters or infinite impulse response (IIR) filters. Conventional FIR filters require large numbers of coefficients to meet the transition band and stopband attenuation requirements. Further, multiple sets of these coefficients are required to support the various coding standards and channel bandwidths. As a result, a large on-chip memory is required. Conventional IIR filters also require many sections to meet such requirements and are sensitive to both coefficient and signal quantization.
For a detailed description of the theory and design of FIR digital filters, see Alan Oppenheimer and Ronald Schafer, Digital Signal Processing (Prentice-Hall 1975), especially chapters 5 and 6. Further information regarding conventional filter design may also be found in:                a Lutovac, M. D. and Milic, L. D., “Design of High-Speed IIR Filters Based on Elliptic Minimal Q-Factors Prototype” (“Lutovac and Milic”), Conf. ETRAN 2002, Banja Vrucica, pp. 103-106 (2002).        b Lutovac, M. D., Tosic, D. V., and Evans, B. L., “Filter Design for Signal Processing—Using MATLAB and Mathematica”, Prentice Hall (2001).        c Harris, F. J., “Multirate Signal Processing—For Communication Systems”, Prentice Hall (2004).        d Krukowski, A. and Kale, I., “DSP System Design—Complexity Reduced IIR Filter Implementation for Practical Applications” (“Krukowski and Kale”), Kluwer Academic Publishers (2003).        e Storn, Rainer, “Designing Nonstandard Filters with Differential Evolution” (“Storn”), IEEE SIGNAL PROCESSING MAGAZINE, January 2005.        